Fujitsu PRIMEQUEST 440, System Design Manual

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C122-B001-02EN 5-25
5.3 Notes on System Design
Entry deletion from the learning table
An entry is deleted from the learning table when one of the following conditions is
met.
Table 5.13 Conditions under which an entry is deleted from the learning table
Transfer of a frame to a port other than the MAC addresses existing in the
learning table
• Symptom
A frame may temporarily be transferred to a port other than the MAC addresses
existing in the learning table.
• Cause
Because a learning table exists for each chip, a mismatch occurs temporarily for the
learning table of each chip.
Remarks:
When a mismatch occurs, the CPU makes each chip relearn the contents of
the relevant MAC address, and therefore a frame transfer to a port other than
those existing in the learning table is a temporary symptom.
Item Deletion conditions
Deletion of an entry Age-out of aging timer
When a frame, which was sent from the relevant
MAC address, has been received from a port other
than an already learned port, due to terminal
movement.
Deletion of an entry learned at a port A link-down has occurred.
The port is set to Disable.
The port has been added to the channel-group.
Deletion of all entries from the learning
table The device has been reset.
VLAN has been changed or deleted.
VLAN mode has been changed.
"Clear bridge" has been issued by a command.
STB reconstruction has begun.